A top Air Force official admitted to Congress that it was "not an appropriate decision" to cut a back-up oxygen system from the original F-22 Raptor fighter design -- a safety system the Air Force is now paying millions to install and one that a dead pilot's family says would've saved his life.

Gregory Martin, a retired Air Force general who headed an official task force to investigate mysterious oxygen problems in the F-22, told the Tactical Air and Land Forces Subcommittee of the House Armed Services Committee last week that a back-up oxygen system was in the original design of the F-22 but had been cut in order to drop weight on the high-performance fighter jets.

"It was not a cost issue," Martin said. "It was true that it was taken out. It did have an initial design of a back-up oxygen [system], in addition to the emergency oxygen system. A series of events occurred, but the catalyst for this particular decision was... the 'war on weight.'"

"In retrospect, that was not an appropriate decision. But at the time, that's what the decision was," he said.

Either way, the sister of F-22 pilot Capt. Jeff Haney said her brother would still be flying today had such a system been present in November 2010 when Haney's primary oxygen system failed just before his plane crashed.

"It would've saved Jeff's life," said Jennifer Haney, who acts as family spokesperson. "My brother would be alive if this would've been something that was in the F-22 from the get-go."

Capt. Haney had just completed a routine training mission in Alaska in mid-November when a still-unexplained malfunction in the plane caused his oxygen system to shut down. Haney never made any distress calls, but a few seconds later he took his jet into almost a direct dive from 51,000 feet. Haney also didn't eject and it appeared he tried to pull out of the dive at the last second, but it was too late, according to an Air Force investigation report. He struck the ground going faster than the speed of sound and died on impact.

Despite the malfunction, the Air Force blamed the crash on Haney, saying he did not properly fly the plane and failed to activate an emergency back-up oxygen system as he fell to the earth. That emergency system, currently an F-22's pilot's only recourse in the event of oxygen system failure at high altitudes, is activated by pulling on a ring tucked into the corner of the cockpit -- a procedure the Air Force admits is difficult even under controlled circumstances, much less while the pilot is tearing through the sky and unable to breathe.

Last month, ABC News reported that an internal document revealed that an Air Force and civilian contractor test group had brought concerns over such a system to the Air Force's attention more than a decade before the crash, citing an "operational deficiency" in the oxygen system design that would go on to play a direct role in Haney's death. The document had suggested the Air Force find another "reliable" source of oxygen for the pilot in case the primary one went down. Beyond the manual emergency system that was already in the planes at the time, the Air Force never did.

"It's really nice of the Air Force to have known about this 12 years ago and then let my brother die," Jennifer Haney told ABC News last month. "That's 10 years before Jeff died that they could've done something and they did nothing. They knew there was a problem with the jet."

Days after ABC News requested comment from the Air Force and from the jet's primary manufacturer, Lockheed Martin, on the internal document, Lockheed Martin settled a wrongful death lawsuit that had been filed by Jeff Haney's widow, Anna. The lawsuit alleged Lockheed Martin and other defense contractors had knowingly provided the Air Force with "defective" and "dangerous" planes. The Air Force was not named as a defendant in the suit and Lockheed Martin said at the time it was filed that while Jeff Haney's death was a tragedy, the company disagreed with Anna Haney's claims.

It wasn't until this May that an Air Force Scientific Advisory Board suggested the service provide the F-22 with an automatic back-up oxygen system. The next month, the Air Force awarded Lockheed Martin a $19 million contract to retrofit the first batch of 40 jets in the fleet with the new automatic system. At the congressional hearing, Gen. Lyon said the entire fleet is expected to be outfitted with the new back-up system by mid-2014.

In addition to Haney's crash, the advisory board had been convened to help explain why, on more than two dozen occasions, F-22 pilots were experiencing "hypoxia-like symptoms" in the cockpit of the advanced fighters. The Air Force has since claimed it has identified the primary problem -- a malfunctioning pressure vest -- but the Air Force officials who testified before Congress admitted that they still don't know exactly what is physically going on with the pilots. Several oxygen-related conditions share a majority of their symptoms and each pilot's account can be different from the others, so a single ailment has been difficult to nail down, they said.

"There will be physiological incidents in the future," Lyon said. "We encounter physiological incidents in all high performance aircraft. It's a fact of life, due to the demands placed on our air crew. The measures taken by the Air Force, in my opinion, will reduce the incident rate significantly and, over time, bring the F-22 incident rates in line with comparable high-performance fighter aircraft."